Estimating Room Impulse Responses from Recorded Balloon Pops

Date:

Fri, 11/19/2010 - 3:15pm - 4:05pm

Location:

CCRMA Classroom, Knoll 217

Event Type:

DSP Seminar

For this week's DSP Seminar, Jonathan Abel will be describing a method for converting balloon pop recordings into room impulse responses. This work was done as part of the Icons of Sound project for the purpose of simulating the acoustics of Hagia Sophia, and an auralization of the Cherubic Hymn (written for Hagia Sophia) will be presented. The seminar will be held 3:15--4:05 PM, Friday, November 19, in the CCRMA Classroom, Knoll 217. Abstract follows.

Balloon pops are convenient for probing the acoustics of a space, as they generate relatively uniform radiation patterns and consistent “N-wave” waveforms. However, the N-wave spectrum contains nulls which impart an undesired comb-filter-like quality when the recorded balloon pop is convolved with audio. Here, a method for converting recorded balloon pops into full audio bandwidth impulse responses is presented. Rather than directly processing the balloon pop recording, an impulse response is synthesized according to the echo density and frequency band energies estimated in running windows over the balloon pop. Informal listening tests show good perceptual agreement between measured room impulse responses using a loudspeaker source and a swept-sine technique, and those derived from recorded balloon pops.